Generally, semiconductor devices are manufactured by selectively and repeatedly performing processes such as vacuum deposition, polishing, photolithography, ion injection, cleaning, inspection, thermal treatment, and the like on the semiconductor wafers; and the wafers are transported to a specific location required for each process in order to be formed as semiconductor devices.
During the semiconductor manufacturing process, the wafers being processed are products of high precision, and they are stored in a wafer storage container such as a front opening unified pod (FOUP) for protection from contamination and damage due to foreign substances and external impact, and then transported for storage or processing.
In this case, process gases being used during the processing and fumes which are byproducts of the processes are not removed, but remain on the surfaces of the wafers and stored in the wafer storage container as they are.
However, proceeding of the processes with such residual materials adhered on the surfaces of the wafers will consequently followed by contamination of the semiconductor manufacturing equipments, failures in the etching pattern, and the like; thus, the reliability of the products will be degraded eventually. Therefore, various technologies for removing such residual materials are being developed.
A wafer storage container for removing fumes remaining on the wafer surface are described and disclosed in the patent literature Korean Patent Publication No. 2010-0134033.
As illustrated in FIGS. 1 and 2, the container portion 64 includes: a shell 65, a closed upper portion, a closed bottom surface, a closed left surface, a closed right surface, an open front surface, and a closed back surface 67.
A door 24 in the open front surface can seal the container portion 64.
A wafer shelf for storing a plurality of wafers may be included inside the container portion 64.
A kinematic coupling plate 74 is located in the bottom of the container and includes an appropriate opening for accommodating the front surface grommet and the back surface grommet 77 in the rearward port 54. The opening is being extended through the shell 65.
The container includes two rearward apertures 80 being extended from the inside of the container towards the outside thereof.
A tube type environment control element 78 configured as a tower element is inserted from the inside of the container portion 64 into the aperture 80.
The tube type element includes a containment portion 81, an offset portion 83, and a port portion 85.
The elastomer grommet 77 may be located in the lower region of the tube type element so as to be sealed hermetically, and a check valve 62 may be located therein.
A cylindrical type filter and/or a getter medial material 10 may be included in the containment portion, and configured to fit into the inside of the tube type element.
The tube type element includes a plurality of axially-extending apertures 11 comprising open horizontal slots.
In addition, the tube type element may include slits for each wafers and the purge gas is discharged at the slit position towards the surface of each wafer.
However, the wafer storage container of the prior art has a problem in that since gas injection area, wafer mounting area, and gas exhausting area cannot form independent space of their own, the gas flow is not uniform inside the wafer mounting area.
Besides, there is another problem in that: a dead zone, wherein the purge gas is not injected to the wafers being stored inside the wafer storage container, may occur; and the purge gas is injected intensively on a specific area since the purge gas is injected by the tube type element being installed vertically.